renege vs undertaking

renege

verb
  • To break a promise or commitment; to go back on one's word. 

  • In a card game, to break one's commitment to follow suit when capable. 

undertaking

noun
  • A promise or pledge; a guarantee. 

  • That which is undertaken; any business, work, or project which a person engages in, or attempts to perform; an enterprise. 

  • The business of an undertaker, or the management of funerals. 

  • The act of one who undertakes (in either sense). 

How often have the words renege and undertaking occurred in a corpus of books? (source: Google Ngram Viewer )